Internet of Vehicles (IoV) is a new-type management service network that is based on a combination of the Internet and the Internet of Things and that integrates a large amount of software technologies and information service content. Conceptually, the Internet of Vehicles is a network, by using a vehicle as a node and an information source and by using advanced sensing technologies, network technologies, and wireless communications technologies, that processes and shares a large amount of information through a vehicle mobile phone to implement “person-vehicle-road-environment-society” internetworking and achieve purposes of identifying, locating, tracing, supervising, and pushing a service in an intelligent manner. To sum up, service functions of the Internet of Vehicles mainly include aspects such as traffic information, a location service, security, a vehicle condition, infotainment, an insurance service, a rider, and a car service. The security service is the most important part of services of the Internet of Vehicles. How to reduce road traffic accidents, and decrease mortality and property losses by using effective information exchange is a most important issue of research on the Internet of Vehicles. To ensure safe driving of vehicles, different vehicles on a road need to exchange some data with each other. Road and vehicle conditions maybe learned by processing these data, such as a vehicle accident ahead; even an accident may be predicted in advance, and then an alarm is given to a driver to make the driver change a driving policy.
The vehicles driving on the road may predict a possible risk in advance by sending a safety message to surrounding vehicles, and avoid the risk. Safety messages of this type may be classified into two types. One type is an event-triggered message, such as an alarm about a static vehicle ahead, an alarm about a low-speed vehicle ahead, an alarm about an emergency brake, and an alarm about overtaking. When these events happen, a vehicle encountering an event generates a corresponding message and informs surrounding vehicles in a broadcast manner, so as to remind the surrounding vehicles of making corresponding avoidance to avoid a possible risk. The other type of message is a periodic status notification message, such as a cooperative awareness message (CAM). The message of this type requires that a vehicle can broadcast its status information, such as a driving speed of the vehicle, a location of the vehicle, a vehicle model, and an acceleration, at a frequency of 1-10 Hz, that is, a cycle of 100 ms to 1000 ms. The surrounding vehicles perform dynamic analysis according to the received status information to discover a possible collision in advance, instead of informing surrounding vehicles after the collision happens. This is preventive.
However, in the prior art, the CAM generally requires a coverage area of 300-500 meters, and considering a scenario of multiple lanes, a quantity of vehicles in a specific area may be 200-1000 vehicles. If a minimum cycle of 100 ms is considered, CAM of 2-10 vehicles need to be broadcasted per millisecond. Such broadcast density may cause a large quantity of message collisions, and consequently receiving vehicles cannot successfully receive these broadcast messages, thereby reducing driving safety.